rough idle, black smoke and juddering

[aaronsummers88]

hi guys,

just after some information brought an a3 2.0tdi with this problem, its got a bit of a rough idle, black smoke when accelerating hard and also judders while under load. fuel consumption isn't very good either. Someone had fitted a new cam belt so checked timing and it was out so sorted that and it took the diesel knock away but still same problems, someones also put a blank plate on for the egg but not sure if its been remapped to tell the computer. EML is on also but would think that is from whatever my problem is. any advice would be appreciated.

Thanks Aaron

[Magnet]

Hello Aaron,

Might be worth having a fairly simple leak-back test on the injectors as a first port of call.

Kind regards,

Gareth.

[Dan3222]

It doesn't look like you have had the fault codes read? If this is true then I think that would be your first step, it may well point to something for you.

But, if it's not injectors I would say either turbo issues or a cracked intercooler.

[aaronsummers88]

I've read it now and comes up with glow plug open circuit #3 would possibly mean a broken wire under the rocker cover? 

[Magnet]

Hello Aaron,

I would have thought that the glow plug issue would only affect the cold starting during low temperature winter months. Could well be wrong.

Kind regards,

Gareth.

[cliffcoggin]

Gareth's thoughts echo my own: glow plugs are only for starting.

[Dan3222]

It would make sense to try to solve the glow plug issue first. These cars have unusual wiring issues. The short here could well be affecting another system.

for example, if I disconnect the front light unit on my T5 (different vehicle I know, but) the main cooling fan comes on!?!

in the mean time check your air filter too. It could be past its best and causing air restriction.

[Magnet]

Good point Dann, but this car has an open curcuit in the glow plug system rather than a short (to earth). Getting this sorted may be dsirable  longer term, but if I recall correctly, the glow plugs only operate when the outside temperature drops to 5 degrees C. 

Kind regards,

Gareth.